Question

Gram Stain Flow Chart for the Organisms: N.sicca, M. luteus, S. epidermidis, E. coli, M. roseus, B. subtilis, B. cereus, S. marcesens, R. rubrum, B. cattarhalis, B. megaterium, S. liquefaciens, E. aerogenes, C. fruendii, E. cloacae, C. xerosis, P. stuartii, A. faecalis

Correct identification of your gram negative bacterium, and the correct identification of your Gram positive bacterium. For each unknown submit two guesses: Choice 1 and Choice 2.

A “Plan of Action”; a schematic representation of what lab procedures you will do to progressively eliminate the bacterial candidates.

Answer 1

Gram staining is the procedure to distinguish and classify the bacteria into two categories namely gram positive and gram negative.Gram staining differentiates bacteria by the chemical and physical properties of their cell walls.

the steps to be followed for the staining procedure is as follows :-

1. Application of a primary stain (crystal violet) to a prior heat-fixed smear of a bacterial culture.
2. Addition of iodide, which binds to crystal violet and traps it in the cell.
3. Rapid decolorization with ethanol or acetone.
4. Counterstaining with safranin.

gram positive bacteria are :- M.luteus,S.epidermidis, M.roseus, B.subtilis, B.cereus, B. megaterium,C.xerosis,

gram negative bacteria are :- N.sicca, E.coli, S.marcescens, R.rubrum, B.cattarhalis, S. liquefaciens,E.aerogenes,C.freundii,E.cloacae,P.stuartii, A.faecalis